So in the images above, we have about 3-4 islands.
Two are stone islands one with a tree, and the other with some pretty nifty chest filled with some pretty sweet items! You can also find a butt load of obsidian on that island! The other two are basic islands for mobs or tree's. Both are made of dirt. The first one you spawn on has 2 trees and a small pond. You can use the pond for a cobblestone generator, and use that cobblestone for getting to the other islands, or tools and weapons.
The other dirt island has a butt load of iron, and has a basic mob spawning system. At the start of it all, 2 cows, 2 chickens (if they haven't died yet,) and 1 sheep should be on that island. At night a bunch of hostile mobs will spawn. Mostly spiders, creepers, and skeletons, and possibly witches!
You can use the sheep for a bed from its wool BUT, do not kill it! Once you have some sheers, you can sheer the sheep for more wool than you can get from killing it. There are also 4 webs on the island, so you should be able to get about 4-5 string, and make a block of wool.
With all the resources you have, you should be able to go to the nether, and kill the wither, and complete the basics of this maps story line.
So, let me lay the basic rules here:

1. DO NOT REUPLOAD MY MAPS, AND CLAIM THEM AS YOUR OWN!2. DO NOT USE CHEATS ON THIS MAP!3. ONLY ABOUT 2-4 PLAYERS CAN PLAY (1 IS RECOMMENDED)4. DO NOT FORGET TO LEAVE CREDIT OR THE MAP'S DOWNLOAD LINK IF YOU MAKE A VIDEO ON MY MAP (NOT THAT YOU WILL, BUT WHO KNOWS?)5. HAVE FUN!Alright, Now that I've gone over that... Let's get over the "challenges" or slight directions that you can follow (unless you want to do this free style...)

1. Try to use only one tree for a crafting table, sticks (tools), and 1-2 large chest.2. Don't make wooden weapons. It'd be much easier getting stone tools AND weapons once you've made a cobblestone generator.3. With a stone pickaxe, mine a good amount of iron, and make a bucket. Once you've done that, make a skyblock cobblestone generator (this should work... Be careful where you put it. I suggest that you put it in the pond on your first island.)4. Make a station of a furnace, crafting table, large chest, and anvil (if you can make that possible. Make a station since a house uses too much resources. You can if you want, but a station is recommended)5. Make a tree farm, and a wheat farm. (Since fire spread is disabled...)6. Fight off any kind of mob with an accurate weapon supply. For example: Arrows, a bow (enchanted if possible,) a sword (enchanted if possible,) and an axe (enchanted if possible.)7. Try to mine the obsidian on the farthest, stone island with out being attacked by mobs. You need a diamond pickaxe, and lucky enough, there are diamonds on this map, they're pretty easy to find, so don't come raging at me in the comments below. They're on that map somewhere...8. Make sure you don't die, in lava especially. You will most likely lose all your items, and never get them back after they've burned in the lava. (Yeah that's right. I didn't add keepInventory on, but I did turn off doFireTick, and there's no way you can turn on keepInventory since you have no permissions >=D)9. Go to the nether, and fight off the Wither. I recommend you doing this IN the nether, If you do this on an island it will most likely get destroyed, and the lava surrounding you will be a big wall in the way of your fight. Welp, those are all the goals or challenges to this map. Let's see if you can follow them...
Thanks for viewing and downloading btw! I really appreciate it!
P.S:
DO NOT ASK FOR THE MC-EDIT/WORLD SAVE FILE IN THE COMMENTS. I DO NOT HAVE THE SCHEMATIC FILE FOR IT! DO NOT RE-UPLOAD MY WORK! THAT IS AGAINST THE RULES (Hopefully it is anyways...)
If there are any bugs in the map, please let me know privately or in the comments below! Have a good one!
Love yall!
-Zatie